Casio Scientific Calculator fx-991ex / fx-991ES PLUS / fx-991MS / fx-82ES PLUS | eBay
Casio FX-991 EX Scientific Calculator with 552 Function Classwiz Spreadsheet | eBay
Original Casio Fx-991ex Advanced Scientific Calculator 552 Functions Engineering Students High School Lab Office Solar - Battery - Calculators - AliExpress
Got ahold of a Casio fx-991ex and CG-50 to match my Classpad II. I'm really impressed with them but there is something about the fx-991ex... (see comments) : r/calculators